Bomb rack



Dec. 19, 1944. l1 E HOFFMAN r- TAL '2,365,409

BOMB RACK 5 sheets-shea 1 Filed Feb. 9. 1942 D. E. HOFFMAN E-rAl.

Dec. 19, 1944.

BOMB RACK Filed Feb'. 9. 1942 5 Sheets-Sheet 2 llnunll H" M lhhlllll Y f n,

@hwk

Dec. 19, 1944.

D. E. HOFFMAN ErAL BOMB RAC K (Filed Feb. 9. 1942 5 Sheets-Sheet 5 VDea. 19, 1944. D E, HOFFMAN ET AL 2,365,409

BOMB RACK Filed Feb. 9, 1942 5 Sheets-Sheet 4 C) i Q l Jaz 27 l Z 195m@ 5,6 RA. fnj/ ze Z5 l Dec. 19, 1944,. D, E, HOFFMAN Em 2,365,409

BOMB RACK Filed Feb. 9. 1942 5 sheets-sheet 5 ZZ' .l 9

Patented Dec. 19, 1944 BOMB RACK Dave E. Hoffman, Los Angeles, and Gordon Throne, Venice, Calif., assignors to North American Aviation, Inc., Inglewood, Calif., a

corporation of Delaware Application February 9, 1942, Serial No. 429,98'0

` -c claims. (ci. sei-1.5)

This invention relates to bomb racks for aircraft and has, as a general object, to simplify and bodiment of the invention, as described in the drawings.

One feature of the invention is peculiar to bomb racks adapted to be electrically actuated for successive release of bombs one at a time. In such racks, it is known to provide a plurality of hooks, each supporting an individual bomb, which is released by'rocking of the hook. The hook is normally locked against rotation into bomb-releasing position by two independent mechanisms, one of which is a safety mechanism movable to simultaneously lock or unlock all the hooks; the other is a firing mechanism operable successively by energization of an electric solenoid to rock the hooks one at a time, if they have been unlocked. Theoretically, the inadvertent energization of the solenoid While the safety mechanism is in lockingposition would have no effect on the hooks. Actually, it has been found that, as a result either of manufacturing tolerances or of wear, the energization of the solenoid while the safety mechanism is in locking position sometimes disable.; the mechanism to such an extent that one or more Abombs may be prematurely dropped at the time the safety mechanism is subsequently moved intoready position. At best, such premature release of a bomb means that it is Wasted. At Worst, it might do serious damage. In accordance with the present invention, premature release of bombs in the manner described is positively prevented by' providing an interlock between the energizing rircuit of the solenoid and the locking mechanism sa that it is impossible to energize the solenoid while the safety mechanism is in locking position.

Another defect of similar prior-known bomb racks adapfed to successively drop different bombs in response to successive movements of a fire control member has been that if the original loading and setting operation was not properly performed, the release of some of the bombs would be prevented.

In accordance with the present invention we prevent the possibility of improperly setting the bomb rack at the time of loading, by providing a safetymechanism that renders the hook inoperative to support a bomb unless the mechanism that controls the sequential release of the bomb has been properly set.

Referring, now, to thedrawings for a detailed disclosure of one embodiment of the invention,

Fig. 1 is a plan view of a bomb rack in accordance with the invention, shown mounted in the wing of an airplane and supporting` five bombs therebelow;

Fig. 2 isa vertical section, taken substantially in the plane II-II of Fig. 1;

Fig. 3 is a detail, plan view of the right end portion of the rack,with parts thereof broken away to better show the construction;

' Fig. 4 is a side elevation of the structure shown in plan in Fig. 3, with portions broken away to better show certain other portions in position for supporting a bomb;

Fig. 5 is an end elevation looking at the right end of Fig. 4;

Figs. 6, 7 and 8 are vertical sections taken in the planes VI-VI, VII- VII and VIH-VIII, respectively of Fig. 4;

Fig. 9 is a horizontal section taken in the plane IX-IX of Fig. 4;

Fig. 10 is a horizontal section taken in the plane of Fig. X-X of Fig. 4;

Fig. `11 is a detail view similar to Fig. 4, but showing the parts in a di'erent position of operation, in which a bomb is being discharged;

Fig. 12 is a view similar to Fig. 11, showing the parts in the position they occupy following discharge of the first bomb;

Fig. 13 is similar to Figs. 11 and 12, except that it shows the parts in position for reloading; and

Fig. 14 is a diagram of the electric circuit of the solenoid for selective discharge of the bombs.

Referring to Figs. 1 and 2, there is shown a portion of a wing 20 of an airplane, within which there is mounted a bomb rack in accordance with the present invention, the rack being positioned just above the lower surface 2|.of the wing and the surface 2| having openings therein through which supporting rings 22 on the bombs can be inserted into engagement with the bomb-supporting hooks of the rack. 'Ihe particular rack shown in Figs. 1 and 2 is adapted to carry ve bombs of the light, fragmentation type. Various k'nown mechanisms may be employed for preventing swinging or other movement of the bombs while supported on the hooks inthe bomb rack, but such devices have been eliminated from the drawings so as not'to confuse the invention.

The main frame of the bomb rack comprises a pair of parallel plate members 23 and 24 (Figs. 2, t, 'l and 8), having their upper edges bent in opposite horizontal directions to form anges 25 and 25. The two plate members 23 and 24 are secured together and to a fitting 21 by bolts 29,

and are also interconnected by various parts to be described later, which are bolted to the anges 25 and 25. To laterally stiften the frame, a shelflike member is extended horizontally from the wall member 24 and secured thereto both by direct attachment, as by spot-welding or riveting, and

' also by brackets 3|.

The under edges of the plates 23 and 24 are provided with a plurality of bomb notches 33 and a plurality of arming wire notches 34. There is positioned between the two plates 23 and 24, adjacent each of the bomb notches 33, a b omb hook 35 pivotally supported on a pin 35 extended through the plates 23 and 24. Each bomb hook 35 has a slot 31 therein which extends horizontally across the bomb notch 33 when the hook is in bomb-supporting position, as shown in Fig. 4; the bomb hook and the notched plates cooperating to lock the ring 22 of a bomb against release.

As shown in Fig. 4, the bomb hook 35 is locked against counterclockwise rotation, which would be necessary to release the bomb, by a lockpin 39 and a trigger lever 49. The lockpin 39 forms part f 43 secured to the frame plate 23. At its right end (Fig. 3) the rod 42 is provided with an eye 44 whereby it may be connected through a suitable o linkage (not shown) with a control handle in the bombardiers compartment of the airplane. It is usually convenient to employ a tension link, such as a cable, for the movement of the rod 42, and

hence it is preferably provided with a helical compression spring (Fig; 4) compressed between a collar 46 on the rod 42 and one of the supporting plates 43, for urging it into leftmost position.

'I'he rod 42 has three operative positions: leftmost. intermediate, and rightmost, respectively. all taken with reference to Fig. 4. The leftmost position is shown in Fig. 4 and is the locking position, in which each of the pins 39 engages a slot 41 in its associated bomb hook 35 and positively prevents rotation of the bomb hook out of bombsupporting position.

When the lock rod 42 is in its intermediate position, each pin 39 is positioned clear of its associated slot 41, as shown in dotted lines at 39a in Fig. 4, so that its associated bomb hook 35 is retained in holding position only by its associated trigger lever 40. When the bombs are to be dropped one at a time, the lock rod 42 is always moved into this intermediate position, in which the pins 39 are clear of both the bomb hooks 35 and the trigger levers 40, and the trigger levers are independently actuated by a mechanism later to be described.

When the lock rod 42 is moved into its rightmost position, the pim 39 engage against the lower ends of the trigger levers 49 and rock them all counterclockwise and release .the hooks 35 .for salvo release of all of the bombs.

Each trigger lever 49 is fulcrumed on a pin 49, extending between the two frame plates 23 and 24, for rocking movement between a hold position and a release position. The lever is shown in the hold position in Fig. 4, in which a shoulder 50 on the trigger bears against a shoulder 49 on the bomb hook 35, to prevent counterclockwise rocking of the hook into release position. Ihe trigger 4lever is shown in release position in Fig. 11, in

which the shoulder 50 on the lever has been disengaged from the shoulder 49 on the hook, and shoulder 49 has come to rest against a shoulder 5I on the lever. In this position an end face 54 on the trigger lever rests against a face 53 on the hook, to prevent return of the leverV into hold position. The lever is constantly urged clockwise into the hold position and the bomb hook is constantly urged counterclockwise into release position, by a tension spring ,stretched between the hook and lever.

The trigger lever 45 has a horizontal face 55 and an adjacent vertical face 51 at its upper end, both of which faces cooperate with an arm 53 on a tripping shaft 59. There are a plurality of arms 59 on'the shaft 59, one for each of the different trigger levers 40, and the different arms 58 extend from the tripping shaft 59 at dierent angles so that only one of them is in -contact with its associated trigger lever at any time. Thus it will be observed in Fig. 4 that whereas the rightmost arm 59 is against the face 55 on the rightmost trigger arm, the next arm 58 to the left is positioned above its associated trigger arm. Stated in another way, when looking at lthe right end of the shaft 59 in Fig. 4 the dliferent arms 58 are angular-ly displaced from each other so thatthey define a right-hand helix.

The tripping shaft 59 is mounted for reciprocal and rotaryvmovement in a plurality of bearing members 60. mounted on the main frame plates, and is yieldably urged longitudinally to the right by a compression spring 5I, and is urged to rotate in a counterclockwise direction (when looking at the right end of Fig. 4) by a torsion spring 52, the latter also supplying a longitudinal force tending to aid the spring 5I.

The compression spring'l surrounds the right end of the shaft 59 and is compressed between a washer 54 held by a pin 55, and a. drum 55, which is slidable longitudinally on the shaft 59 and abuts against the rightmost bearing member 50. The drum 55 is pinned to the shaft 59 for rotation therewith by a pin 51 which extends through an elongated diametrical slot in the shaft 59. 'I'he drum 55 has a. cable wrapped around it which is used to rotate the drum and shaft to reset the latter, which operation will be described later.

The torsion spring 52 also surrounds the shaft 59 and is pinned thereto at one end'by a pin 58, and at its other end ls pinned to the adjacent stationary bearing member 59 by a. pin 59.

An adjustable stop, comprising a ilange 10 secured to the shaft, 59 and a bolt 1I threaded into a stationary bracket 12, limits movement of the shaft 59 to the right in response to the force of the spring 5I. 'I'he position of the shaft can be accurately adjusted by turning the bolt 1I, and the adjustment then fixed by tightening a locknut 13.

When it is desired to release one of the bombs, the tripping shaft 59 is moved to the left by a solenoid 14, which is mounted on the bracket 12 and has a plunger 15 which is drawn into the solenoid when the latter is energized. Adjustably secured to the plunger 15 is a disc head 16 adapted to bear against one end of a rocker arm 11, which is fulcrumed by a pin 18 to the bracket 12. The other end of the rocker arm 11 bears against the right face of the Bange on the tripping shaft, therefore when the solenoid is energized, it moves its plunger to the right, and this motion is transferred through the rocker arm and the ange 18 to the tripping shaft 59, :moving it to the left.

The leftward movement of the tripping shaft 'causes one of the arms 58 in engagement with `its associated trigger lever 4|! to rock the latter counterclockwise into the position shown in Fig. 11, whereupon the related bomb hook is tripped to release its bomb, the bomb ring 22 being shown leavingthe hook. The. first energization of the solenoid always releases the vrightmost bomb. The solenoid is only energized momentarily. Thereafter the tripping shaft 59 is returned to `the right by its spring 6l. During this return movement, the arm 58 slides oif the faceSlfof its associated trigger arm 40 whereupon the torsion spring 82 rotates the shaft 59 to carry the bomb is moved into the bomb notch 33 and against the face 8l on the bomb hook, and rocks the latter into holding position, the trigger lever 40 snaps into the holding position shown in Fig. 4, and locks the bomb hook in holding position so that it will support the bomb.

After the rightmost bomb has been loaded, as

described, the ring 85 is released, and the cable 83 is retracted by a tension spring 92, to bring the ring 85 up snug vagainstdthe bottom surface of the'airplane wing. This `tension spring .92 is relatively light and does not 'prevent thefeeding of the cable 83 back around the drum 66`when I' the latter is subsequently rotated by its torsion next arm 58 to the left into engagement with the face 56 of its associated trigger arm. The next energization of the solenoid then trips the second bomb. The action is repeated with each successive energization of the solenoid to successively release all of the bombs from the rack, one at a time.

When it is desired to reload the bomb rack, the tripping shaft 59 is first restored into its normal position by rotating it against the force of the torsion spring 82, and a bomb ring is pressed in the' rightmost bomb notch. Of course, during this resetting operation, the locking rod 42 is set in the intermediate position shown in Figs. 4, 11, 12 and 13. A

After a bomb has been released, the bomb hook 85 and its associated trigger lever tend to remain in the release position shown in Fig. 12, by virtue of the `force exerted thereon by the tension spring 55. However, when a bomb ring is moved up into the `notch 33 it presses against a face 8| on the hook and rocks the latter into holding position, whereupon the spring 55 rocks the associated trigger lever counterclockwise to engage the trigger lever shoulder 50 against the hook shoulder `48, to thereby lock the hook in holding position.

However, in accordance `with the present invention, we provide a special safety arm 81l for preventing return of the rightmost trigger lever into holding position by the spring 55 until the tripping shaft 59 has been rotated into fully set position. The safety arm 81 is pivotally mounted by a pin 88 to a stationary bracket 89 on the rack frame. This arm 81 is constantly -urged counterclockwise by a torsion spring 9|J,`and when the rightmost trigger lever 40 is rockedl counterclockwise t`o release the rightmost bomb, the up:- per end of the trigger lever is engaged by the outer end of the arm 81, as shown in Fig. l2, to prevent return movement of the trigger lever by the spring 55.*

Thereafter, so long as the safety arm 81 remains in engagement with the trigger lever 4D. the bomb hook 35 cannot be made to support a bomb. Thus, although the pressure of a bomb ring 22 against the face 8| on the `hookwiil rockl `the latter into holding position, the trigger lever spring52 (Fig. 4l when the bombs `are released. After the rightmost bomb has been loaded, the

remaining bombs are loaded into the rack in any desired order by simply moving the supporting ring 22 of each bomb into its bomb notch 33 far enough to restore the associated bomb hook 35 into holding position, each trigger lever snapping intoI holding position in response to movenent of the related bomb hook into holding posiion.

The circuit for energizing the solenoid 14 is shown in Fig. 14, and includes as essential elements: a source of current shown as a battery 93, a safety switch 94, and a bombardier's switch The safety switch 94 is positioned on the bomb rack and is operated by the lock rod 42.

When the lock rod is in locking position, the switch is open, but in all other positions of the lock rod the switch is closed. The bombardiers switch is located in the bombardier's compartment of the airplane, which is usually remote from the bomb rack.

The safety switch 94 is illustrated in Figs. 3 and 4 as beinglof a standard construction comprising a case within 'which contacts are positioned, the contacts being actuated by a push rod 94a extending through a bushing 96 provided therefor on the switch case. The switch is so arranged as to be closed when the push rod 94a is out, and to be open when the push rod is in. The push rod is actuated by a cam 91 provided on the lock rod 42.

As shown in Figs. 3 and 4, the lock rod 42 is in leftmost or locking position, and the cam 91 has depressed the plunger 94a so as to open the switch contacts and prevent any possible operation of the solenoid 14, even though the bombardiers switch 95 (Fig. 14) should be inadvertently closed. However, it will be apparent from Figs. 3 and 4 that in response to movement of the lock rod 42 to the right into the intermediate position, (in which the pin 39 will occupy the position 39a), the cam 91 will be moved clear-'of the plunger 94a permitting the latter to move out and close the contacts within the lswitch case. Thereafter, when the bombardier closes the switch 95 the solenoid will be energized.

It might appear offhand that there would be no necessity for the safety switch 94, because (referring to Fig. 4) even if the solenoid were energized while the lock rod 42 is in locking posimay bepreventedfrom returning to its normal position by engagement of the face ll thereof aaainsttheend surfaceofthebombhook. The reslt of this improper operation would be that when the lock rod Il lis subsequently moved into intermediathe position preliminary to selective tripping of the bombs 'by means of the solenoid, the bomb hook Il would be immediatelyreleasedassoonasthepinllleftthe slot I1.

By providing the safety switch M ais-described, any and all operations of the solenoid are pomtively prevented while the lock rod is in locking position, and any premature tripping of the trigger levers 4I is prevented.

The bomb rack disclod in the drawings is alsoequipped with control means for arming the bomb, this apparatus including an arming rod which is supported for longitudinal sliding movement in the brackets Il that support the lock rod l2. The arming rod is normally maintained in the leftmost position by a compression spring |0I similar to the compression spring Il. In this leftmost position, a plurality of pins |02, projecting from the side of the arming rod, are clear of faces |03 on associated arming levers |04 fulcrumed by pins |05 betweenl the frame plates 23 and 24 of the rack. The lower ends of the levers' |04 have sloping shoulders |00 thereon which normally close the arming notches Si in the rack. The arming wire on each bomb is looped through the aperture delined by the shoulder |06 and the walls of the notch 3l. The arming rod |00 is normally in leftmost, or safety,

position, as shown in Fig, 4, in which the pins |02 are clear of the faces |03 on.the arming levers and the latter are only yieldably held in closed position by springs |01, which yield in response to a pull on the arming rod so that the arming wire is released with the bomb when the latter is dropped. In accordance with well-known practice, the bombs are so constructed that they will not explode unless the arming wire is pulled out of the bomb. L However, when it is desired to drop the bombs in condition to explode, the armim; rod |00 is pulled to the right to carry the pins |02 thereon below the faces |03 on the arming levers |04. This locks the levers against the ing wires from the slots 34, so that when the bombs are dropped the arming wires are retained by the rack and are pulled out of the bombs to condition them to explode in a manner wellknown in the art.

Although for the purpose ofy explaining the invention a specic embodiment'thereof has been described in substantial detail, it is to be understood that various departures from the exact construction shown will appear to those skilled in the art, and the invention is t0 be limited only to the extent set forth in the appended claims.

We claim:

1.` A device of the type described comprising a plurality of bomb-control mechanisms movable between hold and release positions, respectively, safety means movable between safe and ready positions, respectively, for locking said bombcontrol mechanisms in hold pition when said ssfetymeansisinsafepositionandbeingout of operative relation with said bomb-control when in said ready pomtion, a nrlng including lllllllitlvr 0f members 0N! associated with each of said bomb-control mechanisms and movable between a first, normal position in which it maintainsthe asociated bombcontrol mechanism in hold position independently of the safety mechanism associated therewith and a second position out of operativereiation with said bomb-control mechanism, means including electric motor means for moving said firing means from said first to said second posis tions to release said bomb-control mechanisms.

an energizing circuit for selectively energislng said electric motor means, safety switch means connected in series in said energizing circuit, and means for maintaining said switch in open condition while said safety mechanism is in ib safe position.

2. Apparatus as described in claim l, in which said bomb-control mechanism includes a rockable hook member rockable between said hold position and said release position, a first shoulder on said hook member, and means in said safety means engaging said shoulder when the safety means is in said safe position for restraining said hook member against rotation into release position, a second shoulder'on said hook member engageable by said release means when the latter is in its first position for restraining said hook against rotation, said release means being engageable by said hook member in response to release of the hook member by the release member, for preventing return of the release member into holding relation with said hook member.

3. A device of the type described, comprising a bomb-control mechanism movable between hold and release positions, respectively, a safety memclockwise rotation nry to release the armber movable between safe and ready positions, respectively, and engaging said bomb-control mechanism and retaining it in hold position when the safety member is in safe position, a release mechanism including a release member movable between a first, normal position in which it engages said bomb-control mechanism and retains it in hold position, and a second position clear of said bomb-control mechanism, electrically actuated means for shifting said release mechanism into its release position, an energizing circuit for said electrically actuated means, a safety switch in said energizing circuit, and means for maintaining said safety switch in open condition while said safety member is .in its safe position, whereby said release mechanism cannot be actuated into its second position while said safety member is in safe position.

4. A device of the type described, comprising a plurality of bomb-control mechanisms movable between hold and release positions, respectively, a master element movable in one direction through a plurality of selected positions and op-` eratively associated with a different one of said mechanisms in each selected position, means for moving said master element in a second direction and vmeans responsive to such movement for releasing the mechanism operatively associated therewith, spring means responsive to release by said master element of one of said mechanisms for moving the master element in said first direction into operative relation with another of said mechanisms, setting means for 'moving said master element, against the force of said spring,

into an initial position in which it is associated with the rst of said bomb-control mechanisms to be actuated, means associated with said first bomb-control mechanism for retaining said master element in operative relation therewith pending initial movement of said control member in said second direction, means for retaining said first bomb-control mechanism in release position following release thereof by said master control member, and means for'releasing said retaining means in response to completion of resetting movement of said master control member,

5. A device of the type described, comprising a plurality of bomb-control mechanisms movable between hold and release positions, respectively, a master element rotatable through a plurality of selected positions and'operatively associated with a diierent one of said mechanisms in each selected position, means for moving said master element axially, and means responsive to such axial movement for releasing the mechanism operatively associated therewith, spring means responsive to release by said master element of a rst of said mechanisms for rotating the master element into operative relation with another of said mechanisms, resetting means for rotating said master element against the force of said spring means for resetting said master element into initial position in which it is operatively associated with the said first of said mechanisms, means for retaining said first of said mechanisms in release position following release thereof by initial axial movement of said master element,

and means for disabling said retaining means in response to complete resetting movement of said control means.

6. A device of the type described, comprising a plurality of bomb hooks rotatable between hold and release positions, respectively, a latch lever associated with each hook and normally respon- "sive to retain its associated hook in holding poof said latch levers for rotating said master element to bring another arm thereon into operative relation with another of said latch levers, resetting means for rotating said master element against the force of said spring means, and safety means for retaining the said rst latch lever in release position following release thereof by initial axial movement of said master element, said safety means being in the path of said rst arm and movable by said arm out of operative relation with said rst latch lever, in response to complete resetting movement of said control means.

DAVE E. HOFFMAN.

GORDON THRONE. 

